1. Field of the Invention
The present invention relates to a lubricant for sewing machines, which is used for lubricating movable parts that perform their functions in the respective sections of the sewing machines, and more particularly relates to a lubricant for sewing machines, which is suitably used for lubricating slide parts, such as a needle bar and a looper bar, that slide in an axial direction.
2. Description of Related Art
In recent industrial sewing machines, the operation speed is increased to improve the efficiency of sewing work, and satisfactory lubrication of movable parts existing in the respective sections of the sewing machines is an important objective to realize the high speed operation. As a lubricant for lubricating the movable parts of sewing machines, a sewing machine oil or a grease has been used widely (see, for example, Japanese Patent Application Laid-Open No. 2004-155864).
Lubrication using a sewing machine oil is realized by a lubricating structure in which a housing containing movable parts to be lubricated therein is constructed as a liquid-tightly sealed oil chamber, and the sewing machine oil stored in an appropriate part of the oil chamber is guided to a desired movable part by suitable means, such as circulation by a pump, mechanical raising, or guiding the oil by impregnating an oil core with the oil.
Lubrication using grease is realized by a lubricating structure in which a movable part to be lubricated is provided with a grease sealing section, and the grease sealed in the sealing section beforehand is gradually supplied between the relatively moving surfaces of the movable parts. The sealing section is constructed so that the grease is appropriately supplied from outside and the lubricating performance is maintained in a long time.